The invention relates to a process for the manufacture of semiconductor layers on semiconductor bodies or for the diffusion of impurities from compounds into semiconductor bodies, with fission products which are to be withdrawn during the process being formed. The deposition of epitaxial semiconductor layers from the gaseous phase or the diffusion of impurities, for example, from surface layers or from adsorbates at the surface of a semiconductor body, often involves the problem of the formation of reaction products which are incorporated into the semiconductor layers where they cause disturbing electrical properties in the components to be manufactured. In cases where, for example, adsorbates are used an impurity source, the fission products occurring impede the necessary formation of further adsorbates so that only limited impurity concentrations or penetration depths of the doping materials are attainable.
In the epitaxial deposition of silicon layers from chlorosilane, the incorporation of chlorine atoms into the growing silicon layer has proven to be very disturbing. The incorporation of chlorine is caused by the relatively high adherence quotient of the chlorine molecules at the semiconductor surface. These chlorine molecules form, during the splitting-up of chlorosilane, as undesired fission products which are to be withdrawn or removed.